(As I was composing this list, I realized that most... no, all of these fics feature asshole!Jensen. And while I do love asshole!Jensen with unholy passion, anyone who can rec some hate!sex with asshole!Jared gets an extra cookie and my forever love and affection.)
A Second Chance to Make a First Impression by __tiana__ (Jensen/Jared, R, 13,600 words)
Jensen is graduating from college in just four months. When he meets Jared, he does not make a good first impression. Or second. Jared is not interested, or at the very least, unimpressed. Which doesn't actually stop Jensen from trying. He'll do (almost) anything to win Jared over.
Asshole!Jensen in this fic quickly realizes the error of his ways but can't seem to get it right with Jared. It's a wonderfully cute, satisfying college!AU with just the right amount of quasi-angst.
Mating Flight by dragonspell (Jared/Jensen, NC-17, 5,750 words)
Every single time that Carinth, his Green, got ready to rise for another mating flight, J’sen felt like a scared, skittish virgin all over again.
I haven't read the series this story is inspired by, but the writer does such a great job of world building that I didn't miss a beat. Scorchingly hot featuring two incredibly well-matched characters. And dragons!
My Social Skills Would Fit Good In Prison by longsufferingly (Jared/Jensen, R, 8,300 words)
From what Jared understands, his college rooming situation is kind of like The Odd Couple, except for the way Jensen is a homophobic douchebag.
A classic misunderstanding fic that delivers on every nuance of the trope. Featuring a prank war and fantastic dialogue, this fic is a delight!
The Fortress of a High Mind by fourfreedoms (Jared/Jensen, R, 12,384 words)
Jensen and Jared are seniors at an elite private boarding school, competing for the same girl, and they can't stand each other.
In addition to delivering some smoking hot hate!sex, this story features a coming of age for both boys, and the author shows their understanding and growth in a wonderfully subtle, satisfying way.
Can't Get My Head Around You by earthquakedream (Jared/Jensen, R, 6,300 words)
There's always been one constant in Jared's life: he hates Jensen Ackles. It's easy to ignore his attraction to the guy because he's such a bully. When Jared goes to college, he thinks he's finally free, but then Jensen shows up there too and Jared is forced to confront his feelings.
This one starts pretty hurty, and you'll probably hate Jensen's guts for most of it, but it hits all the right notes in getting the boys to where they both want to be.
Maybe This Time by bewaretheides15 (Jared/Jensen, NC-17, ~24,000 words)
There are worse things than being a freshman stuck in the senior dorm. Having three awesomely hot roommates, one of whom can't stand you? Well, that's a whole different ballgame.
Oh, man. This fic hits so many kink buttons. Jensen is a dick, and Jared gives just as good as he gets, and there are tattoos and nipple piercings and surrogate!sex and epic love. So much fantastic in one place.